The present invention relates to brightness control circuits for cathode ray tube display units, more particularly to such circuits suitable for use in high quality video display units.
In brightness control circuits, for video display units, especially for graphics, it is desirable to provide a circuit wherein change of brightness by manual control adjustment control does not upset or change the cathode ray tube current cut-off point insofar as it coincides with a predetermined position of the brightness control. It is desirable to be able to adjust display brightness, for instance to accommodate video signals having a greater amplitude, without changing the current cutoff point or the black level control point.